138087731 has 4 divisors (see below), whose sum is σ = 138146832. Its totient is φ = 138028632.

The previous prime is 138087709. The next prime is 138087757. The reversal of 138087731 is 137780831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 137780831 = 139 ⋅991229.

It is a cyclic number.

It is not a de Polignac number, because 138087731 - 2¹⁸ = 137825587 is a prime.

It is a super-2 number, since 2×138087731² = 38136442905456722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138087431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25895 + ... + 30768.

It is an arithmetic number, because the mean of its divisors is an integer number (34536708).

Almost surely, 2^138087731 is an apocalyptic number.

138087731 is a deficient number, since it is larger than the sum of its proper divisors (59101).

138087731 is an equidigital number, since it uses as much as digits as its factorization.

138087731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59100.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 138087731 is about 11751.0736105260. The cubic root of 138087731 is about 516.8744100185.

The spelling of 138087731 in words is "one hundred thirty-eight million, eighty-seven thousand, seven hundred thirty-one".